| In-depth
studies
‘Temporo mandibular joint
dysfunctions’
‘For
those of you who would like to gain more insight’
Modified from
‘Starbene’- October 1991 – Interview to Prof. Riccardo Ciancaglini
Professor
of Clinical Gnathology – University of Milan
Everything starts, most of the
time, with some noise of the jaw, while one eats or yawns: doctors call it
‘crepitus’. Or with a slight soreness. Or else (but then the problem is more
serious) you may experience the inability to open or close your mouth fully. “If
these symptoms are considered all together, they can be found in 80% of the
population. But the cases that must be treated are less, only 10% of the
population” says prof Riccardo Ciancaglini, full professor of Clinical
Gnathology at the University of Milan. “Until some years ago, the gnathologic
problems taken into consideration included malocclusion and bad habits such as
bruxism, i.e. that unrestrainable grinding of the teeth that can wear them to
the gum. Lately, though, many other defects have been discovered, and today
gnathology is a proper science, with its own wording and with directions for
medical intervention encoded in all the world. The crepitus of the jaw that does
not move regularly (usually called ‘clicking’ and jaw moving difficulties
‘locking’) has been investigated with state-of-the-art diagnostic methods
(arthroscopy, dynamic arthrography, nuclear magnetic resonance) and has been
explained as functional incoordination between the mandibular condyle (the
‘ball’ end of the lower jaw), base of the skull (temporal bone) on which the
mandibular condyle leans, and interposed fibrous disc (intra-articular
meniscus). The mandible is functionally seen, therefore, as the core of the
problem and is defined temporo-mandibular joint or more simply TMJ.
|
%
PREVALENCE OF TMJ SOUNDS IN DIFFERENT AGE GROUPS |
|
(N°2158 Milan Area) AGE
15-80
 |
(FIG
7). Percentage prevalence of sound
(blu) and pain (green) symptoms, grouped in different age ranges; from:
Prevalence and distribution of TMJ sounds in 2158 subjects. R.Ciancaglini
et al. J.of Dental Res. Vol 68 1989.
Note: The main symptoms increase
progressively from childhood to adulthood, while they tend to decrease
spontaneously with old
age.
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The main disorders
(signs and symptoms)
Joint crepitus
“The most
important symptoms in order of severity” states professor Ciancaglini, “are
temporomandibular joint pain and movement difficulties (hyper-mobility and
hypo-mobility).”
Often patients complain of a sort of joint snap or click
that accompanies the pain that suddenly ‘frees’ the jaw with a deviation or
deflection of the chin (S-shaped movement of mouth opening and closing).
Both
pain and movement difficulties can be either unilateral or
bilateral.
Pain
‘Headache’
At first pain can arise occasionally or
while chewing: but in its most severe forms it may become constant or very
intense, just like that of a chronic migraine.
Hypo-mobility as well can
be of different types: in the most serious cases, there may be a true joint lock
that disables regular opening or closing of the mouth.
Ache (pain caused by
palpation of the lower jaw or muscles of mastication or by chewing)
Aching
of the lower jaw and of the muscles involved in its movement during palpation,
joint crepitus; headaches and migraines located in the temporal area (i.e. the
anterior and lateral area of the skull, editor’s note).
Less frequent,
though not rare, are the following symptoms:
tinnitus and
vertigoes
(instability and balance disorders)
pain on one side of the body
impaired
ability to ‘grasp’ of one or both hands
numbness of one or both hands
facial asymmetry
dental mechanism modifications (occlusion)
These
symptoms are often the manifestation of an ‘arthrosic progression of the
pathology’ (Fig. 7). The analysis of the symptoms is very important because it
also involves the assessment of a suitable treatment. “Indeed” Riccardo
Ciancaglini resumes “if everyone who has just one of the listed symptoms is
treated, we would have to intervene massively: it would be like treating, just
to give an example, anyone who has a leg just a few millimeters shorter or
longer than the other.... As a matter of fact, it’s right to treat only those
people who complain of pain or present a serious form of dysfunction (e.g.
hypo-mobility)”.
The groups of people mostly affected by mandibular disorders
are now well known. This type of pathology, indeed, almost never appears before
15 years of age. Later on, its frequency increases with age and reaches its
highest peak between 40 and 45. Then, it tends to decrease, probably because the
body has had time for organizing its own defense system against the disorder. As
for sex, women are slightly more affected, possibly because of a greater
ligament vulnerability.Until some time ago it was believed that mandibular
dysfunctional disorders were due to a defect in dental occlusion. A missing
tooth, badly done bridge-work or fillings, any disorder whatsoever in the
delicate closing mechanism were, indeed, pointed out as responsible for lower
jaw disorders. More recently, advanced studies have amended this
belief.
Window 1-Lower jaw sounds
The best international specialists
of temporo-mandibular disorders can currently take advantage of complex,
state-of-the-art diagnostic equipment.(Fig. 8)
The figure below shows digital
phonarthrometry equipment. It is an oscilloscope that translates every sound
into electrical impulses – even the softest ones, i.e. the ones that an ear is
not able to perceive – produced by the mandible when it opens and closes to chew
or swallow. When computer scanned, not only do electrical impulses reveal the
severity of a possible mandibular disorder, but they also disclose its nature.
This method of investigation has been conceived by professor Riccardo
Ciancaglini in 1984 and is now used by many experts in different
countries.
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Lower jaw
sounds |
 |
Digital oscilloscope |
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(FIG 8) 1 and 2 sound emitted by a diapason, received by
the microphone, and converted into electrical signals by the digital
oscilloscope (note how the signal recurs regularly)
3 and 4 noise
produced by paper crumpling, received by the microphone, and converted
into electrical signals by the digital oscilloscope (note how irregular
the signal is)
5 snapping or clicking sound produced by a
temporomandibular joint dysfunction (with no arthrosic changes), received
by the microphone, and converted into electrical signals by the digital
oscilloscope (note how the signal recurs regularly, just like the sound
emitted by the diapason)
6 crepitus noise produced by an arthrosic
temporomandibular joint, received by the microphone, and converted into
electrical signals by the digital oscilloscope (note how irregular the
signal is, just like the paper noise)
From: Digital
phonoarthrometry of temporomandibular joint sounds: a preliminary report.
R.Ciancaglini et al. J. Oral Rehabilitation, 6: 385-392
1987 |
The most frequent
causes
“The scientific research on mandibular disorders”
confirms professor Ciancaglini “has led to a real revolution with regard to the
opinions that were generally acknowleged in the mid-seventies”. “A first set of
causes of this pathology gathers together all the ‘bad habits of the mandible’,
that is to say, an incorrect use of the joint. The inability to coordinate the
movements of the temporal or masticatory muscles or excessive nervous tension
can bring you to move the TMJ in an anti-physiologic or irregular way. It is
necessary to remember, in particular, that the lower and upper dental arches
should not be kept in contact for longer than five-ten minutes over a 24 hour
span: this ideal time includes both chewing movements during meals and those
seconds of contact during the 1500-2000 daily swallowings. But if teeth are
clenched every day for a much longer time and with more strength than usual,
just like “bruxists” do, that is when the joint may suffer.
“These bad
movement habits”, goes on professor Ciancaglini, “explain why there are
managers, computer technicians, frustrated persons or people exposed to strong
emotional tension among those who suffer from mandibular disorders.”
“A
second set of causes includes so-called ligamentous laxity. (Fig. 9)
There
are indeed many ligaments that connect the upper part of the skull with the
lower part: if these fibrous structures lose tone and elasticity, it is
understandable that the mandible and its movements can run into serious
disorders.
Subject with general
joint hyper-mobility (hand/wrist joints) |
9a. Closed mouth radiography
(tomography) of a temporomandibular joint with hyper-mobility
(subluxation)
9b. Open mouth radiography (tomography) of a
temporomandibular joint with hyper-mobility (subluxation) (Note the
exagerated translative excursion of the mandibular condyle
)
|
“Finally, a third set of causes
is represented by so-called micro-traumas. They are generally accidents of
little account (e.g. a fall, or a blow) that can produce some immediate soreness
right, but that actually end up being forgotten: after a gap of many years,
though, a severe pain or a temporo-mandibular joint lock reveals that there was
a trauma and that it left its mark. Among the many possible microtraumas, we can
also find those small but continuous mechanical stresses due to dental occlusion
defects. But they do not always have a leading role when compared to the other
possible causes of TMJ disorders”. But whatever the cause is, the temporo
mandibular joint deteriorates and gets stuck: “and its nature”, professor
Ciancaglini tells Starbene, “is damage that can be likened to that of an
arthrosic disease. Incidentally, it’s important to remember, first of all, that
the temporo mandibular is a very complex and complete joint, provided with a
meniscus (one on each side, of course) and with very large synovial tissues. We
can roughly maintain that the progression of the disorder, which affects it, is
the same as for any arthrosis. First of all, a lesion of the TMJ synovial and
connective structures is registered, then the meniscus is damaged and lastly, in
the most severe forms, even its bony tissue can undergo a degeneration process.
Nor must we forget that in the temporo-mandibular joint both sides, right and
left, act united. Even though one side is more affected, the opposite side will
suffer, too. “Other structures, too, may be damaged by this kind of disorder,
for example, the masticatory muscles or dentition. But the main target, the one
that has to be treated first if we want to remove pain and moving difficulties,
remains the joint”.
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USEFUL
ADDRESSES |
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Specialists, who have been
interested in mandibular joint disorders for years, are associated in the
American Academy of Orofacial Pain and Craniomandibular Disorders and in
the European Academy for Craniomandibular Disorders. The two societies
together publish a scientific magazine and every year, separately or in
collaboration, they promote an international congress. The main centers of
study and treatment are currently the ones of Zurig and Vienna, of Phoenix
and Ann Arbor in the Usa, and of Goteborg in Sweden. Professor Riccardo
Ciancaglini, whose interview has been published in these pages, is a
member of the most important and qualified international
organizations. |
For a correct
diagnosis
“And here we are, at perhaps the most surprising
chapter of this odontologic super-specialty that deals with the mandible: the
chapter on diagnosis. Today still, a careful clinical exam, an exam carried out
without the help of technical equipment, is no doubt the first useful
approach”.
Manually, the physician examines the joint movement during opening
and closing of the mouth; the joint and connected muscle tissues are also
palpated to spot any painful zone: lastly, the dental occlusion model of the
individual patients is checked. “If well done” argues Ciancaglini, “the clinical
exam can provide 70-80% of the needed information. The same investigation
techniques (which can be classified as physical medicine) should be extended to
the neck area. (Fig. 10)
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|
(FIG 10). 10a. physiological breadth of the bending
extension movement of the head in case of normal mobility of the cranio
cervical joint.
10b. physiological breadth of the rotation movement
of the head in case of normal mobility of the cranio cervical
joint.
10c. Mandibular dislocation test to better hear joint
sounds!!! |
Mobility of the head with
respect to the neck, for example, and mobility of the neck and its muscles have
to be investigated. Often it can happen, in fact, that – parallel to the
arthrosic processes that have affected the temporo mandibular joint – a form of
cervical arthrosis or arthrosis of a tensive origin can develop. It is important
that it be established, also because the location of this pain overlaps those
arising from TMJ disorders, but treatment is of course different in nature”. The
main part, though, is the instrumental diagnosis. Very complex, state-of-the-art
equipment is used today in the diagnostic process by the most qualified
gnathologists. At first glance, professor Ciancaglini’s surgery in Milan, is
literally packed with seemingly unintelligible instruments.....(Fig.
11).
|
|
| (FIG 11).
Electrophysiology equipment (electromyograph, digital oscilloscope,
microphones and amplifiers for phonoarthrometry)
|
“As a matter of fact”,
Ciancaglini confirms, “for medical intervention to be reliable and not based on
a personal opinion, objective diagnostic exams are necessary. Not only must they
provide measurable and reproducible data, but they also have to allow
measurement, during and after treatment, of whether and how much such treatment
has improved the situation. Thus, adequate equipment is absolutely necessary to
serve this purpose”.
“The first exam is the radiographic one:
orthopantomography (or panoramic radiography of the dental arches), oblique
radiographic projections, TMJ’s stratigraphy and if necessary a CAT (computed
axial tomography). As for NMR, where it can be carried out correctly, very
precise information can be provided. It is the chosen exam in the case of
therapeutic decisions (e.g. manipulation under anesthesia, arthroscopy, surgery,
etc.) (Fig.13).
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|
(FIG 13).
13A, 13B. SPECT scintigraphy: normal
symmetric captation of the two TM joints.
13b. SPECT scintigraphy:
hyper-captation, see concentration peak of radioisotope in the chart of a
TMJ affected by condensing osteitis (osteoma-like
tumor). |
“There are other instrumental investigations that can
be considered peculiar to mandibular joint disorders and that have allowed to
advance in their diagnosis: among these, the occlusogram (tek scan)”
(Fig.14).
|
|
(FIG 14). 14a.
Digital occlusion test (computed occlusography) with scanner-like
equipment.
14b. the chart shows frequency and intensity of contact
between teeth in occlusion. |
It is a computerized system
that allows analysis of the location, intensity and sequence of all contacts
between opposing teeth. A different matter altogether is electromyography (EMG),
that is to say, the analysis of the electric currents generated by the activity
of the masticatory muscles correlated with the TMJ. (Fig.15)
 |
(FIG 15).
15. After-stimulus
electromyography: electromagnetic hammer for eliciting the masseterin
inhibitor myotatic reflex (silent period post “jaw jerk”)
15a.
Functional electromyography: rough electromyographic signals showing MVC
of right and left masseter muscles (quantitative analysis will be carried
out with the “root mean square” technique)
15b. After-stimulus
electromyography: post “jaw jerk” silent period length test (with
electromagnetic hammer). Length is measured through a sliding cursor on
the monitor of the digital
oscilloscope. |
Up to ten years ago, much more
was expected from this investigation, but then it was realized to be irrelevant
to a diagnosis, because, in most cases, it is not able to detect the nature of
the disorder.
“But as there is a strict connection between possible joint
damage and the contractile strength of the muscles, electromyography represents
an excellent system to evaluate whether there has been significant improvement.
Extremely useful, eventually, is digital phonoarthrometry of the temporo
mandibular joint, a method of analysis that has been conceived by our work group
since 1984 and is now adopted by many specialists in the world.”
(Fig.16)
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Positioning of the microphones. |
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| 16a Summary chart of the digital phonoarthrometry procedure
for the diagnosis process/ joint noise record conceived by C. et
al. |
16b
phonoarthrometry charts with FFT (“Fast Fourier Transformed”) analysis,
according to the methodology proposed by Ciancaglini et al.: the frequency
spectrum generated by sounds (top figure on the left) and noises (top
figure on the right) is the same as the one for joints with functional
disorders (single noise at bottom left and double noise at bottom
right) |
|
From: Digital phonoarthrometry of
temporomandibular joint sounds: a preliminary report. R.Ciancaglini et al.
J. Oral Rehabilitation, 6: 385-392
1987 |
For “splint” and “bite” treatment
The
investigation carried out by professor Ciancaglini stands out above all for two
characteristics of great importance in the diagnostic process. Firstly, it
allows the detection of joint alteration in a very early stage. Secondly, the
electric reading of sound allows the many types of TMJ alteration to be
distinguished and, in particular, the early forms, generally consisting in
“internal derangement”, from the advanced ones, more unequivocally arthrosic.
And lastly, the chapter on treatment. How can mandibular defects be corrected
?
Since dignostic methods are so advanced, a complex therapy might be
considered: but it is not so... “On the contrary” states Riccardo Ciancaglini,
“in most cases, useful treatment for mandibular disorders amount to
interventions which are inexpensive and technically very simple. More precisely,
it has been scientifically proved that in 70-80 per cent of the forms that can
be classified as serious, functional conditioning – a real educational TMJ
exercise – is able to solve the problem.
“More than orthodontic techniques
(the by now renowned appliances to align teeth), in this case, it is necessary
to think of some kind of orthopedic rehabilitation. Is a joint unable to close
the mouth completely ? Will it be enough to train it to behave differently,
according to a more regular pattern, and in the same way will it act in order to
correct a joint that closes (or opens) without symmetry ?
“The therapeutic
tools of qualified gnathology are, consequently, much simpler than what we may
think. They are usually thicknesses (called bites or splints) that, by modifying
the usual masticatory plane, make the temporo-mandibular joint position itself
and move in a different way from usual” (Fig.17).
|
|
(FIG
17). |
1 occlusal
plate (FLOS type according to Ciancaglini et al. from Concepts of
mandibular and odontostomatologic orthopedics of childhood and age of
development, Ed. CPA 1992) at the end of manufacture (at lab
counter).
2 occlusal plate (FLOS type) applied to the patient’s mouth
with teeth fully in contact (in occlusion)
3 modified HAWLEY’s plate
4 occlusal plate Mares-type (applied to the lower arch)
5
Ciancaglini, Brandazzi, Ceresola’s (CBC) plate: composite resin
“veenering” accomplished on a chrome cobalt casting, on other half-noble
metal or on noble metal (gold, titanium etc.)
6 CBC plate overlaid to
lift up and compensate the vertical dimension. |
Aesthetic integration of CBC plate in the mouth of the patient.
Note the excellent blending of natural teeth and the resin aesthetic
component of the plate. |
The pain symptom as well, in
most cases, is effaced because the application of the bite discharges the area
subject to compression (and therefore irritant) and “frees” the compressed joint
nerves: and this, in turn, helps the recovery of a good functionality.
“Mind
you, the bite must be applied intermittently: never 24 hours out of 24 hours,
but eight or ten hours out of 24. This is a new, very important direction:
otherwise the treatment would fail its purpose, that is to rehabilitate the
joint.
“Only in a few cases, strictly dental intervention is necessary (e.g.
the application of new protheses and correction of the already existing ones) to
definitely change the occlusion model; or, lastly, surgery may be useful for
joints damaged to a greater extent”.
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CONSENSUS CONFERENCE |
|
Consensus
Posture,and Occlusion: Evidence or
Correlation Hypothesis
Milano, May 10
- 1997
Premise
At the present, there is no scientific evidence to support a
correlation between occlusal and postural problems from either a
functional or morphological view. Therefore, there is even less evidence
for a cause - effect. relationship.
This does
not exclude the opportunity to study with a rigorous and meticulous
scientific protocol the problern of the relationship between occlusion and
posture, both in healthy subjects and in
patients.
Clinical implications
In the Iight of the objective, scientific knowledge,
reversible or irreversible occlusal therapies are not justified for the
treatment of postural problems.
Conversely,
physical and rehabilitative therapíes are also not justified for the
treatment of occlusal problems.
Guidelines for
Research
It is therefore appropriate
to direct research specifically towards the study of the correlations
between occlusion and posture rather than towards the study of the single
aspects.
It is necessary to search for
clinically relevant effects through correct research protocols that apply
sustained changes.
European Academy of Craniomandibular Disorders
(EACD)
Società Italiana di ortodonzia
(SIDO)
Società Italiana dí Medicina
Fisica e Riabilitativa (SIMFER) |
 |
|
On 9-10 May 1997 an
International Meeting in Clinical Gnathology “Occlusion, Posture and
Health” was held in the Congress Center of San Raffaele Hospital in Milan
with the Consensus Conference “Occlusion and posture: evidence or
hypothesis of correlation?”. The scientific coordinator of the activity
was professor Riccardo Ciancaglini, who holds the chair of Clinical
Gnathology of the University of Milan and is director of the Oral
Rehabilitation Service of the San Raffaele hospital. The symposium was
promoted jointly by SIDO (Italian Society of Orthodontia) and SIMFER
(Italian Society of Physical Medicine and Rehabilitation) under the aegis
of the European Academy of Craniomandibular Disorders.
The main purpose
of the demonstration was to voice a consensus (hence Consensus
Conference), that is, a position accepted by the scientific societies
involved in a subject matter that is becoming day by day always more the
object of arguments on a medical-legal level. Hence, the need for an
authoritative, reliable opinion that may be a landmark not only for the
professional, but also for the national health
service. |
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